>On 12/8/01 @ 11:52 AM, speedy2 wrote:
>
>Then you've been lucky. Taking a battery pack of rechargable
>cells down past .6V/cell is dangerous "." I have scores of
>data including literature from Sanyo, Duracell, Energizer
>and other companies that show how cell reversal damages
>batteries, etc.
Hi Speedy,
I think you are misunderstanding where I am coming from.
I am not disagreeing with you concerning the cell reversal issue. I know
about it. Been there, done that, got the T-Shirt.
The devices that I've tried this technique on have some sort of circuitry
that informs the user that the battery is getting low. Additionally, the
devices will automatically shut down when it gets to a certain point to
preclude this from happening.
I am not talking about some cheap device that has no internal circuitry
for this and merely die when the voltage gets too low.
Let's disregard the other devices, and just look at the MP2K which I
believe that the original message was about.
Would Apple have purposely designed the Newton so that it could easily
discharge the battery below a safe level where one of the cells would
reverse itself? No way. This would be a huge financial mistake for them
as they would be replacing numerous batteries, and possibly more.
I mean, how many times have you turned on a Newton and found the battery
to be dead? Happens all the time with my spares. If there is not enough
voltage, the Newt will simply not turn on.
If everytime this happened, there was a strong possibility that the
batteries would go bad because one cell would reverse itself, Apple would
be shooting itself in the foot.
>Advice from these companies not withstanding, myself and numerous other
>engineers who *design* equipment with or for re-chargable batteries can
>attest to ill-effects of cell reversal(as in, we've seen it first hand).
>
>This advice comes from the engineering world, so it's not hocus pocus.
Again, I am not disagreeing about the battery reversal point.
Totally agree that they can and will do that given the appropriate
conditions.
Also, if you will recall, my suggestions were for the person who was
already experiencing problems with his primary and back up battery.
This was a last ditch effort to keep the battery working. It is not
something that you would do on a regular basis.
>Many devices (like Walkmans, CD players, etc) have low-battery warnings
>and beyond some voltage, fail to operate simply because they *need*
>sufficient voltage/current to run and the batteries will no longer do.
>
>However, because the unit turned off at a certain point, doesn't mean it
>used smarts to do it, the it's very likely the batteries just could drive
>the units anymore (thus the unit could have taken the batteries down
>beyond a certain point).
True, no disagreement here.
And that is why if you are using Alkaline batteries, once they are no
longer usable in your Newt, you can use them in another device that
requires less voltage rather than throwing them away.
>If you still want to discharges you batts all the way go ahead,
>just be aware of what might happen.
Appreciate your concern.
However, I am not worried in the least. I've done it with too many
rechargeable battery packs used in devices, that have some sort of
intelligent battery management circuitry, over the years to worry about
it.
Respectfully,
Sushi
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